As disclosed by the present inventors in Japanese Patent Laid-Open Nos.136,240/87, 152,536/87 and 152,537/87, conventional dehydration methods using anhydrous saccharides are those wherein a dehydrating activity is utilized, said activity being exerted by allowing an anhydrous saccharide to absorb moisture from a hydrous matter to convert the anhydrous saccharide into a hydrous crystalline form. Unlike heat drying, these methods require no heating conditions and have a merit of converting hydrous matters into dehydrated products without deterioration or degeneration of their quality.
It was found that among the above-mentioned methods the method using anhydrous aldohexoses such as anhydrous glucose or galactose as disclosed in Japanese Patent Laid-Open No.152,536/87, attains a satisfiable dehydration of a relatively-large amount of water and readily induces the maillard reaction because such an anhydrous aldohexose has a reducing property and a relatively-high reactivity to substances such as amino acids or peptides; and because of these, there exists an anxiety about the stability of the resultant dehydrated product. It was also found that anhydrous aldohexoses are not convertible into hydrous crystalline aldohexoses even at an elevated humid condition, and only exert a poor dehydrating-activity. It was found that in case of using anhydrous maltose as disclosed in Japanese Patent Laid-Open No. 136,240/87 and in case of using anhydrous paratinose as disclosed in Japanese Patent Laid-Open No. 152,537/87, there still remains an anxiety about a long-term stability of the resultant dehydrated product because anhydrous maltose and anhydrous paratinose, even if they have a relatively-low reducing activity, are basically reducing sugars. It was also found that the amount of moisture absorbed by anhydrous maltose or anhydrous paratinose is relatively low, i.e. about 5 w/w % with respect to the amount of the anhydrous maltose or the anhydrous paratinose, and because of this such saccharides have a demerit that it should be used as a desiccant in a relatively-large amount.
It may be speculated that anhydrous non-reducing glycosylfructosides such as anhydrous raffinose, anhydrous erlose and anhydrous melezitose as disclosed in Japanese Patent Laid-Open No. 152,537/87 have no reducing activity and do not react with amino acids and peptides, and this imparts them a satisfactory shelf-life without inducing the maillard reaction. Anhydrous glycosylfructosides, however, have a fructoside bond with a relatively-low acid tolerance in their molecules, and this may lead to an estimation that the anhydrous glycosylfructosides are not necessarily suitable as a desiccant for acid hydrous matters. In this case, there still remains an anxiety about stability in the resultant dehydrated products.